The present invention relates to a gas-insulated switchgear apparatus, in particular, to a gas-insulated switchgear apparatus having a sealed container in which at least a breaker portion, a current transformer, and an earthing switch for maintenance and inspection are together contained.
In gas-insulated switchgear apparatus of the recent days, a current transformer and an earthing switch for maintenance and inspection are accommodated in a sealed container, which is originally provided for containing a breaker portion, for the purpose of decreasing the mounting area occupied by the apparatus.
A gas-insulated switchgear apparatus of this kind is disclosed in Japanese Patent Unexamined Publication No. 60-213205, where the sealed container has a cylindrical shape with its axis situated substantially horizontally, and contains therein a current transformer together with a breaker portion for working opening and closing actions in a vertical direction. Further, the cylindrical surface of the container, namely the upper or lower portion of the container, is formed thereon with branch nozzles, with which main bus bars are to be connected, and a side surface (end surface) of the container is connected with a line side terminal portion.
In the gas-insulated switchgear apparatus mentioned above, the mounting area for the apparatus may be decreased, but the height of the same becomes rather higher, because branch nozzles are provided on the upper or lower portion of the horizontally situated sealed container for introducing the main bus bars into the container. In addition, there is a problem that it is somewhat difficult in manufacture to form cylindrical branch nozzles on a cylindrical surface of the sealed container. Further, since, at the connecting portions between the sealed container and the branch nozzles, there may be generated a higher electric field concentration on the earthing side, it is required to locate the main bus bars in the container or connecting conductors extending to line side connecting terminals considerably apart from the wall surface of the container for avoiding the high electric field concentration. In consequence, the connecting conductors are formed in complicated bended shapes for assuring sufficient clearances from the wall of the container and from other devices arranged in the container, thereby causing a complex structure inside of the container.
Japanese Patent Unexamined Publication No. 60-183908 discloses a gas-insulated switchgear apparatus of the above-mentioned type, where main bus bars are connected with a side surface of a sealed container. In this gas-insulated switchgear apparatus, the sealed container has as cylindrical shape with its axis situated vertically and contains therein a breaker portion working opening and closing actions in a vertical direction and a current transformer. Further, the cylindrical surface of the container is formed on one side portion thereof with a branch nozzle, with which the main bus bars are connected, and on the other side portion with a branch nozzle, with which the line side terminal portion is connected.
In the gas-insulated switchgear apparatus mentioned above, the height of the apparatus may be decreased, but the mounting area for the same becomes rather greater, because branch nozzles are provided on the side portion of the sealed container. Further, the above-mentioned disadvantages still remain also in this apparatus, because the cylindrical branch nozzles are 0 formed also on the cylindrical surface of the sealed container for connecting main bus bars and line side terminal portion with the container.
Since a gas-insulated switchgear apparatus of this type is generally installed in the inside of a house, small size of the mounting area and the low height of the apparatus are desired.